The present invention relates to a solution processing apparatus and method for performing solution processing such as developing processing and the like for a substrate such as a semiconductor wafer or the like.
A mask for forming a circuit pattern on a front face of a semiconductor wafer (hereinafter, referred to as a wafer) or an LCD substrate of a liquid crystal display is formed by the following process. Initially, coating of a photoresist solution (hereinafter, referred to as a resist) is performed for a front face of a wafer and irradiation with light or the like is performed. If the resist is a negative type by way of example, a portion thereof irradiated with light is cured, and a portion not cured, which is an easy-to-dissolve portion, is dissolved with a developing solution, whereby an object mask is formed. A developing processing apparatus comprises a spin chuck for suction-holding and rotating a semiconductor wafer and a developing solution supply nozzle for supplying a developing solution to the semiconductor wafer on the spin chuck.
Conventionally, a supply nozzle 12 in which many discharge holes 11 are arranged over a length corresponding to a wafer W in a diameter direction shown in FIG. 9B is used as the developing solution supply nozzle used in a developing process as described above.
The discharge of the developing solution by the supply nozzle 12 will be explained with FIG. 9A. The supply nozzle 12 is positioned so that the discharge holes 11 are, for example, 1 mm above a front face of the wafer W at the middle portion of the wafer W, and the wafer W is rotated 180 degrees while the developing solution is supplied from the discharge holes 11 to a middle portion in the diameter direction of the front face of the wafer W. Thereby, the developing solution is spread all over the wafer W while being discharged from the middle portion over the diameter direction of the wafer W, thereby completing solution heaping. Simultaneously, a solution film of the developing solution with a predetermined thickness is formed on the entire front face of the wafer W.
Incidentally, a conventional process of heaping of the developing solution all over a top face of the semiconductor wafer is in need of causing a total stay time of the heaped developing solution to be uniform as much as possible to obtain uniformity of line width. To this end, the developing solution needs to be rapidly applied to the semiconductor wafer, and thus a supply pressure of the developing solution is kept high.
However, in the conventional developing processing method, the developing solution supply nozzle is arranged such that the discharge holes thereof are small in diameter and the supply pressure thereof is set high for the sake of uniform discharge, resulting in high discharge flow velocity. Therefore, an impact on a dissolved portion of the front face of the semiconductor wafer is high at the time of initial discharge to the front face of the semiconductor wafer, whereby the uniformity in line width is susceptible to decreasing.
Further, there exists a portion where the first discharged developing solution and the last discharged developing solution are overlapped within an area close to the middle of the semiconductor wafer under the supply nozzle, whereby old and new developing solutions are mixed and thus developing proceeds in the portion more than in other portions, thereby also bringing about a danger that uniformity in line width of the area close to the middle deteriorates.
Additionally, since the developing solution is discharged while the semiconductor wafer is rotated, solution face waviness occurs at the time of heaping of the developing solution caused by inertial force of the developing solution. As a result, there occurs an area where the developing solutions are vigorously mixed or an area without such vigorous mixture, thereby bringing about a disadvantage that the uniformity of the developing becomes worse.
Therefore, it is a conceivable case to employ coating means as shown in FIG. 10 using the same developing solution supply nozzle as the aforementioned. FIG. 10 shows a scan method in which the supply nozzle 12 is moved to the outside of the rim of the wafer W to be placed and further moved therefrom to the outside of the rim of the wafer on the other side while performing discharge.
The apparatus shown in FIGS. 9A and 9B has a cylindrical cup 13 around the wafer W and a series of developing processing is performed in the cup 13. The cylindrical cup 13 is a component for preventing a liquid from splashing out and collecting a splashed rinse liquid in a rinse process in the case where the rinse liquid is discharged while the wafer W is rotated after the completion of the developing processing.
However, in the case where the processing method as shown in FIG. 10 is performed in such a cylindrical cup 13 disposed near the substrate, when the supply nozzle 12 is allowed to scan from an initial discharge position to the rim of the wafer W on the other side, the supply nozzle 12 lies off the cylindrical cup 13 in an area close to a discharge start position and an area close to the completion position where the supply nozzle 12 is tangent to the rim of the wafer W, thus the developing solution leaks out of the cylindrical cup 13 as shown by the diagonally shaded areas a in FIG. 10, thereby making a developing unit dirty.
Further, if the cylindrical cup 13 is increased in size, more specifically, the cup is increased in size to cover areas a, there arises a disadvantage that the developing unit must be upsized.
An object of the present invention is to provide a solution processing apparatus and method capable of preventing upsizing of the apparatus and preventing a processing solution from leaking outside the apparatus when a supply of the processing solution is performed by scanning a wafer with a supply nozzle having a supply area with a length of almost the same as a diameter of the wafer or more.
To achieve the above object, a solution processing apparatus according to the present invention comprises: a substrate holding section configure to horizontally hold a substrate and rotatable; a cup configure to surround the side of the substrate held by the substrate holding section; a nozzle extending along one side of the inside of the cup configure to supply a processing solution to the substrate; a moving mechanism configure to move the nozzle along a side adjacent to the one side of the inside of the cup; a raising and lowering mechanism configure to raise and lower the substrate holding section and the cup relative to each other; and a control mechanism configure to control a position in height of the cup relative to the substrate through the raising and lowering mechanism, between a level where an upper side of the cup is positioned by the side of a moving area of a discharge hole of the supply nozzle, and a level where a lower side of the cup is positioned by the side of the substrate.
According to the apparatus as described above, the supply nozzle moves in the upper side of the cup, thereby preventing the processing solution from leaking outside the cup and reducing an occupied area by the cup.
The apparatus may be arranged in the following manners: The cup is formed such that the upper side thereof is formed in a rectangular shape and the lower side thereof is formed in a cylindrical shape. When seen the cup from above, the portion forming the cylindrical shape is positioned within the portion forming the rectangular shape. The supply nozzle includes a supply area of the processing solution with a length corresponding to a width of an effective area of the substrate to supply the processing solution to the entire effective area of the substrate while moving from a waiting position off the effective area of the substrate. The apparatus further comprises a rinse liquid supply mechanism configure to supply a rinse liquid to the rotating substrate after the processing solution is supplied. An air supply section configure to supply clean air to a front face of the substrate is provided above the substrate and an exhaust port configure to perform exhaust is provided below the substrate, the clean air from the air supply section descending toward the substrate and being exhausted from the exhaust port via the cup. The apparatus further comprises: a rotation mechanism configure to rotate the substrate holding section; an exhaust mechanism configure to exhaust air between the substrate holding section and the cup; and an exhaust control section configure to operate the exhaust mechanism based on operation information of at least one of the rotation mechanism and the raising and lowering mechanism.
A solution processing method according to the present invention comprises: horizontally holding a substrate by a rotatable substrate holding section and surrounding the side of the substrate by a rectangular portion that is an upper side of a cup; supplying a processing solution to the substrate while a nozzle extending along one side of the inside of the cup is moved along a side adjacent to the one side of the inside of the cup; and surrounding the side of the substrate by a cylindrical portion that is a lower side of the cup by raising the cup relative to the substrate holding section to stabilize flows of air streams from above.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.